Planer knife grinder



Oct. 25, 1960 N. B. NELSON PLANER KNIFE GRINDER Filed Sept. 9, 1957 FIGB Mn O S 6 mN B ATTORNEY PLANER KNEE GRINDER Nolan B. Nelson, Hilltop Road, Rte. 7, Greensboro, N.C.

Filed Sept. 9, 1957, Ser. No. 682,845

9 Claims. (Cl. 51-55) This invention relates to a planer knife grinder and more particularly to a planer knife grinder and knife holder combination in which a plurality of knives may be ground by revolving a rotatable knife supporting carrier in juxtaposition to the plane of grinder wheel rotation.

Hog knives, planer knives and other types of lumber dressing knives or blades are usually sharpened by supporting the knives at an appropriate angle on a flat work supporting table and the table is linearly reciprocated beneath a rotating grinding wheel so that the circular face of the wheel will grind the knives that are supported at the requisite angle. Frequent dressings of the grinding wheel are necessary where the circular face of the grinding wheel comes in contact with the knives and careful adjustment to compensate for the difference in blade thickness always presents a problem in mounting the blades on a flat supporting bed. Also, it is extremely difiicult to grind a curvature or to hollow grind a knife edge with the conventional flat work supporting table unless the grinding wheel is dressed with the proper contour.

Therefore, it is an object of this invention to provide a knife grinder in which a plurality or set of knives may be accommodated on a single rotatable knife carrier for presentation of the knives successively to a rotatable grinding wheel.

Still another object of this invention is to provide a rotatable knife supporting holder and a revolving grinding wheel wherein the rotatable knife supporting holder will revolve at a selective angular velocity and the knives supported on the holder will be ground uniformly across a fiat circular end face of the grinding wheel to grind a specific cutting angle on the knives.

This invention further contemplates the provision of a knife grinder in which the grinding wheel may be adjustably oriented to a specific angular disposition with respect to the plane of rotation of the knife holder and mounted to pivot in response to the angular position of the knife holder in order to grind a curvature or bevel surface on the cutting edge of the work blades being ground.

A further objective of this invention is to provide a massive knife supporting carrier on which a plurality of knives may be supported for presentation to the end flat face of a grinding wheel.

Another objective of this invention is the provision of a compact, sturdily constructed knife grinder that is simple to operate, one which saves considerable time in mounting knives into position on a rotatable knife holder and one which requires a minimum of maintenance.

Other objects and many of the attendant advantages of this invention will become more readily apparent to one skilled in this art from the following detailed description of one preferred embodiment of this invention taken in conjunction with the accompanying drawing in which like characters of reference refer to corresponding parts throughout the several views, and wherein:

Fig. 1 is a front perspective view of the knife grinder of this invention illustrated in one position for grinding a Patented Oct. 25, 1960 2 flat bevel on planer blades supported on a knife carrier;

Fig. 2 is an end elevational view of the upper section of the grinder of Fig. 1 illustrating a mechanism for pivoting the grinding attachment;

rug. 3 is a side elevational view of Fig. 2;

Fig. 4 is an enlarged partial transverse sectional view taken substantially along the plane of section line 4-4 of Fig. 2; and

Fig. 5 is a modification of the knife carrier illustrated in Fig. 4 to include an auxiliary mounting for supporting additional knives to be ground.

Referring to the drawing and particularly to Fig. 1 there is illustrated a knife grinder for planer knives and the like comprising a massive cast base 10 on which a motor-driven grinding wheel attachment 11 is mounted on a lower level portion of the base and a revolvable knife supporting turntable or knife supporting carrier 12 that is mounted in spaced relation to the grinding wheel attachment to revolve about a horizontal axis.

Base 10 is preferably cast to provide ground engaging pads 32 and at least two vertically spaced work supporting surfaces with the upper level 13 having a pair of journal pillar blocks 14 fastened by means of bolts 15 to the base for rotatably supporting a knife supporting carrier shaft 15 therein. Knife supporting carrier 12 is securely fastened through a hub 17, mounted on the carrier, to one end of the shaft 16. In the embodiment illustrated the knife carrier 12 is a quadri-laterally shaped casting in which one face 18 is suitably machined to receive a number of wedge-shaped knife supporting members 19 each of which is securely fastened to the face 13 adjacent to the carrier perimeter 20. Each of the knife supporting members 19 has a right triangular cross-section and the hypotenuse or long side 21 is suitably grooved at intervals to form spaced apart tracks 22 for receiving spacer shims 23 therein to adjust for the height of an individual knife to expose the edge to be ground with relation to the wedge members. Members 19 may be securely fastened to the face 18 of carrier 12 by means of bolts 24 passed through openings 25 drilled in the members 19 with the bolts making threaded engagement with tapped holes 26 in the carrier face.

A planer knife 27, illustrated in Figs. 1, 3 and 4, may be supported on the carrier 12 with the back edge resting against the shim 23. The knife may be secured to the Wedge-member 19 by means of a U-shaped cleat 28, having a bolt 22 therein that threadably engages an opening (not shown) in the member 19 to retain the knife in position during grinding. It is preferred that a number of spaced cleats be employed to anchor each knife in position before grinding, as shown more clearly in Fig. 1.

Perimeter 24} of the carrier 12 has rounded corners 30' and a number of tapped spaced apart openings 31. Where straight edge or flat bevel cutting edges are to be ground on a large number of planer knives, an auxiliary knife-supporting member 33, as in Fig. 5, may be mounted on the perimeter 20 of the carrier 12 by passing bolts 34 through openings 35 in the member 33 to threadably engage within the tapped openings 31. Additional knives 36 may be supported, in a manner similar to that described above, against the side 37 of the auxiliary knife supporting member 33 to supplement the knives 27 supported on the member 19. As evident from Fig. 5, the cutting edges of the knives 27 and 36, on the members 19 and 33 respectively, will be exposed in close relation to each other for grinding engagement by the flat end face 38 of the cylindrical grinding wheel 39 mounted on the attachment 11, as clearly shown in Fig. 5

An inverted U-shaped bracket 4% is mounted intermediate the pillar blocks 14 on the upper level 13 of the base to straddle the shaft 16 for supporting an electric motor 41. Motor 41 has a motor shaft on which a conoff the carrier transmitted to thetcradle by means of the ventional spring-loaded variable pitch pulley 42 is mounted. A speed reduction gear box or transmission 43 is mounted on the other end of the shaft 16 and retained in position by means of the bracket 44 that is fastened to the base 10. Pulley 45 is keyed on the input shaft 46 to the gear box 43 and a flexible connector or V 'oelt from the driving variable pulley 42 will rotat e the pulley 45 to transmit power from the motor driven variable pitch pulley 42 to the pulley 45 on the gear box to drive the shaft*16' which will revolve the carrier 12 at the desired angular speed. 7

At the lower level 47 of the base casting a pair of spaced apart upstandin lugs 48 that have been bored horizontally form a yoke for receiving a shaft 49 therein for pivotally supporting a carriage. or cradle bed 51 from which'carriage depending lugse l extend downwardly for'cooperatively. receiving the end of shaft 4-9 therein. Carriage 50 is articulated so that the lower section 52'isjsupported to pivot about a horizontal axis parallel to the axis of the knife'carrier shaft 16 and the upper section 53, while'pivotable with the lower section, is pivotallyhingedto the lower section adjacent to face 18 of the knife carrier through depending lugs 54 and 55, respectively, and the hinge rod 56 extending through the lug openings. The other end of the upper section 53 has'a depending bracket 57 bolted along one side thereof with the bracket having an arcuate elongated slot 58 thereinfor receiving the guidebolt 59' that is fastened to the lower section 52.

For conventional straight or bevel edge knife grinding, the upper and lower sections 52 and 53 will be securely fastened together so that the pads 59 and 60 are contiguous and the guide bolt 59 will be fastened to prevent parting of one section relative to the other, as shown in Fig. 3.

A grinding wheel motor supporting carriage 61 is slidably supported through suitable cooperating guideways 62 forlongitudinal movement of the carriage 61 upon actuation of the indexing crank handle 64 and threaded rod 65 that is rotatably supported on the bracket 66 extending vertically from the end of the upper section 53 with the rod '65 'threadably' engaging within the rodreceiving bracket 67 on the upper surface of the slidable carriage 61. a a

Electric 'motor 69 having an extending shaft 7t! is securely fastened to the slidable carriage 61 for movement toward and away from the working supporting surface 18 of the knife carrier 12. The cylindrical grinding wheel 39 having a flat end face 38, with a conventional central cavity 74 for receiving a plate or flange (not shown) for fastening the wheel to the motor shaft 70, is mounted in spaced relation to the work-supporting face of the knife carrier. 4

'For hollow grinding of knives wherein the peripheral edge 38 of the grinding wheel 39 is utilized, it will be necessary to attach an upwardly and outwardly extending guide arm 75 to the side of the lower section 52; of the pivotable cradle bed 50 by means of the bolts 76. The upper end of the arm has a cam follower roller 77 thereon which is intended to engage the camming perimeter 20 of the knife carrier during rotation thereof in order to pivot and locate the cradle d a predetermined distance from the axis of carrier rotation. The selected degree'of curvature or, concavity desired in the knife edge may be set by elevating the upper section 53 of the cradle with respect to the lower section 52, with the requisite angular inclination being indicated by suitable indicia 78 inscribed on the bracket57 and the lower section. As the upper section is tilted upwardly about the hinge rod 56, the edge 38 of the grinding wheel will be tilted toward the knife edge so as to grind a concave cutting edge as the carrier rotates and the cradle is pivoted in response to the camming actionrof the perimeter guide arm 75.

For those applications of grinding where it is desirable to grind a straight bevel edge on the knife, the cradle 50 may be locked in a horizontal position by means of the bolt 59' and the bolts 80 and 81 threadably retained within the base lugs 48 and cradle lug 51. Obviously other means for fastening the cradle in position for straight bevel grinding may be used to maintain the cradle in a horizontal position.

A suitable sheet metal housing to enclose and guard the operating components is contemplated both with respect to a single housing to cover all. of the operating devices as Well as a housing through which ready access may be obtained to the carrier to facilitate knife changes.

Obviously many. modifications andtimprovements may be made in the construction and arrangement of the knife carrier and the means for supporting the knives thereon as well as the motor-driven grinding wheel attachment in the light of the above teachings without departing from the realspirit and purpose of this invention. Such rearrangement of parts and alternatives as well as the use of mechanical equivalents to those herein illustrated are reasonably included and modific'ationsare contemplated.

What is claimed is:

1. A planer knife grinding machine comprising, in

combination, a pedestal base having a first'and a second level spaced vertically from each other, a shaft rotatably supported in a horizontal position on the second level of the base and overhanging at one end from the base, a quadrilaterally-shaped work holder supported at the said overhanging end of the shaft for rotation therewith, said holder having a plane surface normal to the shaft, elongated wedge-shaped knife-receiving elements fastened to the planesurface of the holder adjacent to the perimeter thereof,jeach of said elements being'adaptable to receive a planer knife or the like to expose a portion thereof beyond said holder perimeter at a selected angle, releasable clamping means for retaining a knife on said element, motor-driven variable speed driving means for rotating said'shaft, a cradle mounted to pivot about a horizontal ax s supported on the first level of the base, a carriage mounted on said cradle for slidable move ment axially of the cradle, means for incrementally displacing said carriage, a motor having an extending grinding wheel supporting shaft mounted on said carriage, and a grinding wheel supported on said shaft, said grinding wheel being rotatable in a plane parallel to the plane of rotation of said holder for grinding engagement with the exposed portions of knives mounted in position on the holder.

2. A planer knife grinding machine comprising, in combination, a pedestal base having a first and a second level spaced vertically from each other, a shaft rotatably supported in a horizontal position on the second level of the base and overhanging at one end from the base, a quadrilaterally-shaped work holder supported at the said overhanging end of the shaft for rotation therewith, said holder having a plane surface normal to the shaft, elongated wedge-shaped knife-receiving elements fastened to the plane surface of the holder adjacent to the perimeter thereof, each of said elements being adaptable to receive a planer knife or the like to expose a portion thereof beyond said holder perimeter at a selected angle, releasable clamping means for retaining a knife on said element, means for rotating said shaft, a cradle mounted to pivot about a horizontal axis supported on the first level of the base, a carriage mounted on said cradle for slidable movement axially of the cradle, means-for incrementally displacing said carriage, a motor having an extending grinding wheel supporting shaft mounted on said carriage, and a grinding wheel being rotatable in a plane parallel to the plane of rotation of said holder for grinding engagement with the exposed portion of knives mounted in position ,on the holder.

3. A planer knife grinding machine of the character described comprising, in combination, a base, a motordriven grinding wheel attachment mounted on the base, said attachment including a shaft, a grinding wheel having a flat end face supported on the shaft of said attachment, means for displacing the grinding wheel attachment axially, a knife-supporting carrier shaft rotatably supported on the base in spaced parallel relation to said grinding attachment, a knife-supporting carrier having a plurality of knife-supporting stations adjacent to the periphery of the carrier mounted on the carrier shaft for presenting a knife to the flat end face of the grinding wheel, a motor-driven variable transmission means for driving said carrier shaft to present a knife supported on the carrier for engagement with the flat end surface of the grinding wheel during rotation of the shaft.

4. A planer knife grinding machine of the character described comprising, in combination, a base, a motordriven grinding wheel attachment pivotally mounted on the base, a grinding wheel having a fiat end face mounted on the attachment, said attachment also being tiltable normal to the direction of the attachment pivotal movement, a shaft mounted on the base in spaced relation to the pivotal axis of the attachment, a motor-driven variable speed transmission means for driving said shaft, a multi-sided knife carrier mounted to evolve in a plane parallel to said grinding wheel and having means thereon for supporting a knife at each side and for presenting a supported knife at a selected angle to the flat end face of the grinding wheel, and means on said attachment for engaging the perimeter of said carrier for pivoting the attachment in response to the position of a knife being ground whereby a curvature may be ground in the knife.

5. A planer knife grinding machine of the character described comprising, in combination, a base, a motordriven grinding wheel attachment pivotally mounted on the base, said attachment also being tiltable in the direction normal to the pivotable displacement, a cylindrical grinding wheel having a fiat end face mounted on said grinding wheel attachment, means for incrementally displacing said grinding wheel attachment, a shaft mounted on the base in spaced relation to the grinding wheel attachment, a knife carrier supported for revolving in a vertical plane about a horizontal axis and having means thereon for supporting a plurality of knives adjacent to the perimeter of the carrier mounted at one end of said shaft, and means on said attachment for engaging said carrier for pivoting the attachment in response to the position of a knife being ground in relation to the edge of the grinding wheel.

6. A planer knifer grinding machine of the character described comprising, in combination, a base, a motordriven grinding wheel attachment mounted on the base, means for incrementally displacing the grinding wheel attachment axially, a grinding wheel having a flat end face mounted on the attachment, a knife supporting work holder having a plurality of knife supporting stations rotatably mounted in spaced parallel relation to the plane of rotation of the grinding wheel, means for revolving said work holder independently of the grinding wheel, and means on said work holder for releasably securing a knife at a suitable angle for grinding engage- 6 ment with the grinding wheel end face upon rotation of the work holder.

7. A planer knife grinding machine of the character described comp-rising, in combination, a base, a slidable carriage mounted on the base, a motorriven grinding wheel attachment mounted on the carriage, means for incrementally displacing the carriage to advance or retract the attaclnnent, a grinding wheel having a flat end face mounted on the attachment, a knife supporting work holder having a plurality of knife supporting stations rotatabiy mounted in spaced relation to the grinding wheel attachment and grinding wheel, said work holder having a side facing and parallel to said grinding wheel and a periphery normal to said side, and means on said side and periphery of the workholder for supporting knives thereon for presentation to the grinding wheel end face.

8. A knife grinding machine comprising, in combination, a pedestal base having a first and a second level spaced vertically from each other, a knife carrier rotatably supported for rotation in a Vertical plane on the second level of the base at one end thereof, elongated wedge-shaped knife-receiving elements fastened to the carrier on one side thereof facing said base adjacent to the carrier perimeter, each of said elements being adapted to receive a planer knife or the like to expose a portion thereof beyond said holder perimeter at a selected angle, clamping means associated with each of said elements for retaining a knife thereon, means for rotating said carrier, a cradie mounted to pivot about a horizontal axis supported on the first level of the base, a carriage mounted on said cradle for slidable movement axially of the cradle, a motor having an extending grinding wheel supporting shaft mounted on said carriage, and a grinding wheel supported on said shaft in juxtaposition to the carrier, said grinding Wheel being rotatable in a plane parallel to the plane of rotation of said carrier for grinding engagement with the knives mounted in position on the carrier.

9. A knife grinding machine comprising, in combination, a base having an upper and a lower level, a knife supporting carrier revolvably supported about a horizontal axis on said upper level, said carrier having a polygonical periphery, a plurality of individual holder means for supporting a knife mounted adjacent to the periphery of the carrier to expose a portion of the knife, means for rotating said carrier, a motor-driven grinding wheel attachment having a grinding wheel mounted thereon supported on the lower level of the base for movement toward and away from the vertical path of travel of the carrier for grinding the exposed portion of knives mounted on said carrier, said grinding wheel and carrier being revolvably mounted in spaced parallel relation to each other, and means on said attachment for displacing the grinding wheel toward and away from the carrier.

References Cited in the file of this patent UNITED STATES PATENTS 2,161,947 Bower June 13, 1939 2,334,938 Lang Nov. 23, 1943 2,481,936 Lord Sept. 13, 1949 2,579,337 Reaser et a1 Dec. 18, 1951 

